The present invention relates generally to cardiac valve replacement in heart surgery, and particularly to a valve assembly kit consisting of a plurality of specialized surgical instruments used for a reproducible, standardized technique to rapidly assemble a heart valve in the operating room from autologous tissue.
In recent years, cardiac valve replacement surgery has become a common procedure. Many cardiac valves are now replaced with valves constructed from autologous tissue. xe2x80x9cAutologous tissuexe2x80x9d is any tissue harvested from the human or animal subject such as heart valves, pericardium, arteries, veins, organ capsules and the like, which is intended to be reimplanted in the same subject. The mitral valve is one such valve that has been constructed from autologous tissue.
The mitral valve is generally a thin continuous, flexible membrane, strengthened by collagen fibers, surrounding the left atrio-ventricular ring having two indentations or commissures dividing it into two principal trapezoidal leaflets of unequal size. The details of the mitral valve anatomy are described in U. S. Pat. Nos. 5,344,442 and 5,500,015 to Radu Deac, which are incorporated herein by reference and assigned to the same assignee as the present application. Under normal conditions, the mitral valve is exposed to the greatest pressure and stress during the cardiac cycle. However, in comparison with aortic, tricuspid and pulmonary valve replacement procedures, mitral valve replacement procedures have exhibited the poorest results in terms of morbidity and mortality.
The ideal valve substitute should be designed to reproduce as accurately as possible the normal flow pattern in the left side of the heart. The valve should have a large orifice, unrestrictive to a central free flow. It should operate at a low opening pressure without gradients across the valve, and be compatible with high outputs at exercise. The valve should exhibit rapid opening and closure throughout its entire range of pressures without regurgitant flow and without obstruction to the left ventricular output flow. The ideal valve substitute should be attached to the papillary muscles in such a manner as to maintain the valvular-papillary muscle continuity with a minimum of stress to thereby preserve the mechanics and contractural movement of the left ventricle. The valve should provide a uniform distribution of forces and stresses and avoid compressive, tensile or flexure stress during operation. The ideal valve should be constructed entirely of flexible tissue, without mechanical stents and the like. It should exhibit a long life, be durable, resistant to wear and resistant to degeneration, calcification and infection. It should provide normal heart sounds, without noise. It should produce no thrombo-embolic complications, and avoid trauma to blood elements. It should function normally as the left ventricle changes in size. The ideal valve should be easy and reliable to produce and implant.
The prior art replacement heart valves and techniques for forming such valves do not meet these criteria because of the difficulties involved in harvesting, forming, and implanting a suitable valve in the operating room. Thus, there is a need for a sterile valve assembly kit that can rapidly assemble a heart valve in the operating room, at the time of the mitral valve replacement, from autologous tissue.
The present invention is a valve assembly kit consisting of a plurality of specialized surgical instruments used for a reproducible, standardized technique to rapidly assemble a heart valve in the operating room from autologous tissue. The specialized surgical instruments of the valve assembly kit of the present invention are used to tailor, process (preserve) and assemble an autologous pericardium heart valve in relation with the anatomical configuration of the left ventricle and mitral annulus. The valve assembly kit generally consists of a tissue processing tray that supports the following specialized surgical instruments/devices: a tissue cutting device, an obturator with a removable handle, a valve assembly tray, and a universal stentless valve holder. These specialized surgical instruments will be used to rapidly (15-20 min.) assemble a heart valve in the operating room, at the time of the mitral valve replacement, from autologous tissue.